understand

To know the meaning of; to parse or have parsed correctly; to comprehend.

Can you repeat what you just said? I didn't understand.

Thus, when he drew up instructions in lawyer language, he expressed the important words by an initial, a medial, or a final consonant, and made scratches for all the words between; his clerks, however, understood him very well.

To know the meaning of; to parse or have parsed correctly; to comprehend.

‘[…] I came back here, had a wank and finished that book.’ ‘The Naked Lunch?’ ‘Yeah.’ ‘What did you reckon?’ ‘Crap.’ ‘You’re just saying that because you didn’t understand it,’ said Adrian. ‘I’m just saying that because I did understand it,’ said Tom. ‘Any road up, we’d better start making some toast.[…]’

To be thoroughly familiar with; to be able to undertake properly.

The students understood the assignment.

To comprehend a fact or principle; to regard or come to regard a belief as such.

I understand that company policy says I can't get a refund, but can you make an exception?

There's been no formal declaration, but it's understood that a state of war exists between the two countries

To know the intent, motives or character of; (of events) to know the causes of or reasons for.

One day you say you love me, the next you ignore me—I don't understand you!

Uh-huh, I see; a way to acknowledge something said by the other speaker.